DULUTH, Minn. (AP) — Authorities believe an attack that left a Duluth store owner bloodied was perpetrated by a woman who bought synthetic drugs from the retailer.

The 34-year-old woman was arrested on a possible assault charge Wednesday night for allegedly attacking Jim Carlson, owner of the Last Place on Earth.

Carlson tells the Duluth News Tribune (http://bit.ly/1agqv8x ) he has a restraining order against the woman after she tried breaking into his shop previously. Court records show the woman was charged last month with possessing a synthetic drug and trespassing.

Police Chief Gordon Ramsay says that with the clientele that visit Carlson’s store, it’s surprising that similar incidents don’t happen more often.

A city ordinance requiring Carlson to get a license to sell synthetic drugs is now in effect. Carlson is challenging the ordinance in federal court Friday.